Merge branch 'array-context' into visualization-vtk-lagrange-array-context

doc/array.rst

doc/index.rst

examples/plot-connectivity.py

examples/simple-dg.py

meshmode/array_context.py

meshmode/discretization/__init__.py

meshmode/discretization/connection/__init__.py

meshmode/discretization/connection/chained.py

meshmode/discretization/connection/direct.py

meshmode/discretization/connection/face.py

meshmode/discretization/connection/opposite_face.py

meshmode/discretization/connection/projection.py

meshmode/discretization/connection/refinement.py

meshmode/discretization/connection/same_mesh.py

meshmode/discretization/poly_element.py

meshmode/discretization/visualization.py

meshmode/distributed.py

meshmode/dof_array.py

meshmode/mesh/generation.py

meshmode/version.py